Automatic sheet polishing machine



March 31, 1964 A, M, ELUOTT AUTOMATIC SHEET POLISHIVNG MACHINE Filed March 27, 1963 INVENTOR. z'ar/ZZu/orz United States Patent Office 3,126,564 AU'EMATIC SHEET PGLISHING MACHINE Aibert M. Elliott, Linthicum Heights, Md., assignor to Eastern Stainless Steel Corporation, Baltimore, Mtl., a corporation of Maryland Filed Mar. 27, 1963, Ser. No. 268,322 Claims. (Cl. 15-102) This invention relates to a sheet polishing machine and more particularly, to a machine which automatically and positively holds the ysheet against the polishing device.

In polishing a sheet of material, a number of different individual operations must be performed. Among these are moving the sheet to expose all of the areas to be polished, and positioning the surface being polished in proper Contact with the polishing device,

This invention provides an integrated arrangement in which the sheet is moved to expose dirmterent surface areas to the polishing device, the sheet being automatically held in positive contact with the polishing device during the polishing operation.

Another object of the invention is to insure that only prescribed lengths of sheet are polished.

Another object is to provide an arrangement for conveying a sheet past a polishing surface wherein positive contact between the sheet and the polishing device is achieved and the possibility of the polishing device contacting the conveying apparatus is eliminated.

Further objects and the entire scope of the invention will become more fully apparent when considered in light of the following detailed description of the illustrative embodiment of this invention and from the appended claims.

The illustrative embodiment may be best understood by reference to the accompanying drawing which is a side elevation view of an automatic sheet polishing machine embodying the invention.

Briey, the invention comprises a pair of conveyor belts positioned end to end, the end of one conveyor being joined to that of the second conveyor through pivotal connections to an intermediate platen. This platen is positioned below a polishing device and is movable towards and away from the polishing device under the control of switching devices associated with the conveyors, to positively force the surface to be polished against the polishing device.

Referring no-w to the drawing, the apparatus may be described in detail. A pair of conveyor supports 16 and 12 are spaced a distance apart, the member 10 serving as a front support and member 12 being a rear support. Pivotally connected to the front support is one end of a rst conveyor frame 14 carrying a roll 16. This roll is suitably driven by a gear motor drive 18 mounted on the front support lil. On the other end of the iirst conveyor frame 14 there is carried a second roll 26. The latter end of the first conveyor is pivotally mounted within a recess 22 in one side of a metallic platen 24, which is preferably made of aluminum. The upper surface of platen extends above the conveyor `to clamp the material to be polished to the polishing device as will be described in detail below. Mounted on rolls 16 and 20 is a conveyor belt 26 to which is applied appropriate tension by an idler roll 2S mounted on frame 14. Also mounted on frame 14 is a pinch roll cylinder 30 carrying a pair of pinch rolls 32 and 34 positioned on opposite sides of the belt such that a sheet of material to be polished passes on the belt between the rolls. The pinch rolls are operatively connected to a limit switch 36 such that when the sheet passes between rolls 32 and 34, the switch 36 is actuated. The limit switch 36 is connected to a linear timer 38 which is regulated by the speed of the conveyor to measure the rate of travel of the sheel 3,126,564 Patented Mar. 3l, 1964 2 along the associated conveyor belt 26. This timer serves to control a solenoid operating valve (not shown) which operates a platen cylinder 4t) to raise or lower the platen 24 to which the cylinder 49 is operatively connected.

The remaining portion of the conveyor arrangement is precisely the same as that just described. Pivotally connected to the rear support 12 is one end of a second conveyor frame 42 carrying a roll 44. As in the case of the corresponding roll 16 of the first conveyor frame, roll 44 is suitably driven by a gear motor drive 46 mounted on the rear support 12. To the other end of the second conveyor frame 42 there is connected a second roll 43. The end of the second conveyor remote from rear support 12 is pivotally mounted in a recess 50 on the other side of platen 24 such that the upper surface of the platen extends above the conveyor. A conveyor belt 52 is mounted on rolls 44 and 45, the tension on belt S2 being controlled by idler roll S4 connected to frame 42. A pinch roll cylinder 56, carrying rolls 58 and 60 arranged similarly with respect to belt 52 as rolls 32 and 34, is also mounted on frame 42. The pinch rolls are operatively connected to a limit switch 62 which is operated when polished sheet material passes between the rolls 58 and titl. Limit switch 62 operates linear timer 64 which cooperates with timer 38 to control the solenoid operating valve operating the platen cylinder 4G. In the embodiment shown, actuation of limit switch 36 results in the energization of the solenoid operating valve to raise the platen, whereas the actuation of limit switch 62 deenergizes the solenoid operating valve and causes the platen to be lowered.

The pivotal connections of the conveyor` frames 14 and 42 and arrangements of the supports 10 and 12 must be such that on displacement of the platen, freedom of movement is provided for the conveyor frames. In the embodiment shown in the drawing, this is accomplished by pivotal connections of the supports 10 and 12 to fixed bases. These connections are clearly shown in the drawing and provide means for displacing the pivotal connections between the conveyor frames and the supports when the platen is raised or lowered. It is obvious that a number of other arrangements may be provided for allowing freedom of movement of the conveyor frames when the platen is displaced.

Now that the structure of the inventive embodiment has been described, a typical cycle of operation will be outlined. Drive motors 18 and 46 are arranged to drive the conveyors such that belt 26 serves as an entry conveyor belt `to move a sheet of material towards the polishing station, and belt 52 serves as a discharge conveyor belt moving the sheet of material away from the polishing station. In this embodiment the polishing device is illustrated as a contact roll 66 over which a polishing belt 63 rides. However, it will be understood that other suitable polishing devices may be employed as, for example, a polishing wheel positioned immediately above the platen.

A sheet of material of known length to be polished is placed on the entry conveyor belt 26 which is operating at a predetermined speed. As the leading edge of the sheet passes ybetween pinch rolls 32 and 34, the limit switch 36 starts the linear timer 38 which is regulated by the speed of the entry conveyor belt 26. The distance between the pinch rolls 32 and 34 and the center line of the polishing device, which in this case is the center line of the contact roll, is known. Therefore, at the end of a period required for the leading edge of the sheet to reach the center line of the polishing device, the timer 318 energizes the solenoid operating valve controlling the movement of the platen cylinder 4i) to raise the platen 24 thereby clamping the sheet between the platen and the polishing belt 68 with a force suicient to insure thorough polishing impeding the transport of the sheet.

The sheet continues its travel under the polishing belt to polish the upper surface of the sheet, the movement of the discharge conveyor belt 52 assisting that of the entry conveyor belt 26 to transport the sheet.

As the leading edge of the sheet passes between pinch rolls 58 and 60, the limit switch 62 is actuated to start the linear timer 64. Since the speed of bolt 52 and the distance between the center line of the polishing device and pinch rolls 58 and 60 are known, the timer is used to measure the length of the sheet in process. As either the trailing edge of the sheet, or a prescribed length thereof, reaches the center' line of the polishing device, the timer 64 de-energizes the solenoid operating valve controlling the platen cylinder 4t) to lower the platen 24 thereby releasing the sheet from contact with the polishing device. This insures that the platen will not come in contact with the polishing device when the entire sheet is being polished, or that only the prescribed length of the sheet is polished when it is desired to polish only a portion of the sheet.

As each new sheet of material is deposited on the entry conveyor belt 26, the above described sequence is repeated.

The above-described embodiment is illustrative of a preferred embodiment of the invention but it not intended to limit the possibilities of insuring that positive contact between the sheet and the polishing device is obtained. It will be appreciated that the inventive arrangement is equally applicable to the grinding of sheet material by the simple substitution of a grinding element for the polishing device in the described machine.

The automatic sheet polishing machine disclosed herein is an example of an arrangement in which the inventive features of the disclosure may be util-ized, and it will become apparent to one skilled in the art that certain modifications may be made within the spirit of the invention as defined by the appended claims.

What is claimed is:

1. An automatic sheet polishing machine for polishing a sheet of material comprising: a polishing device, a first conveyor means for transporting said sheet to said polishing device, a second conveyor means for transporting said sheet away from said polishing device, a platen between said first and second conveyor means over which the sheet passes during transport, said platen positioned adjacent to and spaced from said polishing means; said first conveyor means including a conveyor belt frame, a support member, one end of said conveyor belt frame being pivotally connected to said support member and the other end of said frame being pivotally connected to said platen, a roll at each end of said conveyor belt frame, drive means for one of said rolls, and a conveyor belt mounted on said rolls; means responsive to the presence of the sheet on said first conveyor means to move said platen to clamp said sheet of material between the platen and said polishing device, means responsive to the presence of the sheet on said second conveyor means to move said platen to release the sheet of material from contact with said polishing devi, and means associated with said conveyor belt frame and said support member for permitting displacement of the pivotal connection between said support member and the frame on movement of said platen.

2. An automatic sheet polishing machine for polishing a sheet of material comprising: a polishing device, a first conveyor means for transporting said sheet to said polishing device, a second conveyor means for transporting said sheet away from said polishing device, a platen between said first and second conveyor means over which the sheet passes during transport, said platen positioned adjacent to and spaced from said polishing means; said second conveyor means including a conveyor belt frame, a support member, one end of said conveyor belt frame being pivotally connected to said support member and the other end of said frame being pivotally connected to said platen, a roll at each end of said conveyor belt frame, drive means for one of said rolls, and a conveyor belt mounted on said rolls; means responsive to the presence of the sheet on said first conveyor means to move said platen to clamp said sheet of material between the platen and said polishing device, means responsive to the presence of the sheet on said second conveyor means to move said platen to release the sheet of material from contact with said polishing device, and means associated with said conveyor belt frame and said support member `for permitting displacement of the pivotal connection betwecn said support member and the frame on movement of said platen.

3. An automatic sheet polishing machine for polishing a sheet of material comprising: a polishing device, a first conveyor means for transporting said sheet to said polishing device, a second conveyor means for transporting said sheet away from said polishing device, a platen between said first and second conveyor means over which the sheet passes during transport, said platen positioned adjacent to and spaced from said polishing means, means responsive to the presence of the sheet on said first conveyor means to move said platen to clamp said sheet of material between the platen and said polishing device, said platen including a metallic member having recesses in opposite sides thereof, said first conveyor being pivotally connected to said platen within one of said recesses and said second conveyor being pivotally connected to said platen within the other of said recesses, the upper surface of said platen extending above the level of said conveyors to clamp said sheet of material to said polishing device when said platen is moved in response to the presence of material on said first conveyor means; and means responsive to the presence of the sheet on said second conveyor means to move said platen to release the sheet of material from contact with said polishing device.

4. An automatic sheet polishing machine for polishing a sheet of material comprising: a polishing device, a first conveyor means for transporting said sheet to said polishing device, a second conveyor means for transporting said sheet away from said polishing device, a platen between said first and second conveyor means over which thc sheet passes during transport, said platen positioned adjacent to and spaced from said polishing means, means responsive to the presence of the sheet on said first conveyor means to move said platen to clamp said sheet of material between the platen and said polishing device, and means responsive to the presence of the sheet on said second conveyor means to move said platen to release the sheet of material from contact with said polishing device; each of said means responsive to the presence of material on said conveyors including a pinch roll cylinder mounted on its respective conveyor means, a pair of pinch rolls carried by said pinch roll cylinder, said pinch rolls positioned with respect to said conveyor means such that the material during transport passes between said rolls and engages at least one of said rolls, a limit switch responsive to the engagement of said material with the pair of pinch rolls, and a linear timer actuated by said limit switch to measure a prescribed length of material passing said pinch rolls; a solenoid control valve connected to each of said linear timers to control the direction of movement of said platen in response to the measurement of the prescribed lengths of material by said linear timers.

5. An automatic sheet polishing machine for polishing a sheet of material comprising: a polishing device, a first belt conveyor for transporting said sheet to said polishing device, a second belt conveyor for transporting said sheet away from said polishing device, a movable platen positioned between said first and second belt conveyors and pivotally connected thereto, the upper surface of said platen extending above said conveyors and located adjacent to and normally spaced from said polishing device; a platen cylinder operatively connected to said platen to selectively move the platen in a vertical direction, means responsive to the presence of a sheet of material on said first belt conveyor to move said platen upwardly to clamp said sheet of material between the platen and said polishing device, and means responsive to the presence of the sheet on said second belt conveyor to move said platen downwardly to release said sheet of material from Contact with said polishing device, each of said responsive means comprising a pinch roll cylinder mounted on the respective belt conveyor, a pair of pinch rolls carried by said pinch roll cylinder, said pinch rolls positioned with respect to said conveyor such that the material during transport passes between said rolls and engages at least one of said rolls, a limit switch responsive to the engagement of said material with the pair of pinch rolls, and a linear timer actuated by said limit switch to measure a prescribed length of material passing said pinch rolls; a solenoid control valve connected to each of said linear timers to control the operation of said platen cylinder, said solenoid control valve being energized to raise said platen when the means associated with said rst belt conveyor responds to the presence of material thereon and being de-energized to lower said platen when the means associated with said second belt conveyor responds to the presence of material thereon.

References Cited in the iile of this patent UNITED STATES PATENTS 2,095,697 Hammer Oct. 12, 1937 2,335,196 Pecsok Nov. 23, 1943 2,340,121 Hamilton Ian. 25, 1944 2,453,339 Peterson Nov. 9, 1948 2,972,200 Beks Feb. 21, 1961 

1. AN AUTOMATIC SHEET POLISHING MACHINE FOR POLISHING A SHEET OF MATERIAL COMPRISING: A POLISHING DEVICE, A FIRST CONVEYOR MEANS FOR TRANSPORTING SAID SHEET TO SAID POLISHING DEVICE, A SECOND CONVEYOR MEANS FOR TRANSPORTING SAID SHEET AWAY FROM SAID POLISHING DEVICE, A PLATEN BETWEEN SAID FIRST AND SECOND CONVEYOR MEANS OVER WHICH THE SHEET PASSES DURING TRANSPORT, SAID PLATEN POSITIONED ADJACENT TO AND SPACED FROM SAID POLISHING MEANS; SAID FIRST CONVEYOR MEANS INCLUDING A CONVEYOR BELT FRAME, A SUPPORT MEMBER, ONE END OF SAID CONVEYOR BELT FRAME BEING PIVOTALLY CONNECTED TO SAID SUPPORT MEMBER AND THE OTHER END OF SAID FRAME BEING PIVOTALLY CONNECTED TO SAID PLATEN, A ROLL AT EACH END OF SAID CONVEYOR BELT FRAME, DRIVE MEANS FOR ONE OF SAID ROLLS, AND A CONVEYOR BELT MOUNTED ON SAID ROLLS; MEANS RESPONSIVE TO THE PRESENCE OF THE SHEET ON SAID FIRST CONVEYOR MEANS TO MOVE SAID PLATEN TO CLAMP SAID SHEET OF MATERIAL BETWEEN THE PLATEN AND SAID POLISHING DEVICE, MEANS RESPONSIVE TO THE PRESENCE OF THE SHEET ON SAID SECOND CONVEYOR MEANS TO MOVE SAID PLATEN TO RELEASE THE SHEET OF MATERIAL FROM CONTACT WITH SAID POLISHING DEVICE, AND MEANS ASSOCIATED WITH SAID CONVEYOR BELT FRAME AND SAID SUPPORT MEMBER FOR PERMITTING DISPLACEMENT OF THE PIVOTAL CONNECTION BETWEEN SAID SUPPORT MEMBER AND THE FRAME ON MOVEMENT OF SAID PLATEN. 